When and by whom was Greek fire first used in battle?

For the first time, a prototype of Greek fire was used at the Battle of Delia as early as 424 BC. The creation of the Greek fire belongs to a Byzantine engineer who was able to invent this combustible mixture in 673. It is known that the Byzantines often used this weapon against the Russians who went to Constantinople. An interesting fact is that in our time the secret of “Greek fire” remains unknown.